Golf club head with adjustable center of mass

ABSTRACT

The golf club head with an adjustable center of mass provides for player adjustment of club action according to the position of an adjustable weight or mass within the club head. A hollow, “metal wood” type club head includes an open receptacle in the sole wall, with an L-shaped arm and mass installing in the receptacle. The arm includes a club head attachment end that attaches within the receptacle, and a weighted end, which extends into the interior of the club head. The L-shaped arm may be turned about its mounting axis to orient the weight or mass to the front, rear, left, or right within the club head, or to some intermediate position therebetween. The adjustably positionable mass alters the collective center of gravity of the assembly to affect the draw, fade, and loft tendencies of the club, as well as affecting the vibratory characteristics of the club.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to equipment and implements used in the game of golf. More particularly, the present invention relates to a golf club head with an adjustable center of mass.

2. Description of the Related Art

As the game of golf has become more popular, more has been learned about the various subtleties and nuances involved in its play. All golfers use clubs of two basic types in order to optimize their play, i.e., “irons” and so-called “woods,” named for the historic compositions of their club heads. Irons were, and still are, formed of a ferrous metal, with stainless steel being a common material in modern clubs. “Woods” were historically formed of a solid mass of wood (persimmon wood being a popular choice) with somewhat larger and often more massive weighted club heads than irons for use in driving the ball from the tee.

More modern “wood” club heads are usually not formed of wood at all, but are often formed of thin wall, hollow metal castings or forgings. Such club heads are generally called “metal woods,” as they have the external configuration of a historic wood club head while being constructed of metal. The use of metal in the construction of such club heads provides numerous advantages in strength and durability, and the hollow head allows various masses to be installed within the club head in order to affect its performance.

In the past, various club manufacturers have made numerous attempts to “fine tune” the action of a metal wood type club, by installing various weights and masses within the club head. Generally, these masses were immovably affixed within the head, thus allowing no further tuning or adjustment of the effect of the added weight or its position within the head of the club. A few manufacturers have provided for movable or adjustable weights within the club head in order to seek the potential advantages that might be provided by such a configuration.

An example of a golf club head having a movable weight is illustrated in French Patent No. 2,716,808, published on Sep. 8, 1995. A mallet-type golf putter is illustrated, having opposed lateral bores to each side of the central club shaft attachment. Weights may be installed in the bores adjacent to the central shaft attachment area of the club head to affect the balance of the putter. The weights are held in place by springs installed outboard of the weights, holding the weights inwardly toward the attachment end of the shaft. No rotary adjustable weight about a vertical axis is apparent.

Japanese Patent No. 11-197,276, published on Jul. 27, 1999, illustrates a metal wood-type club head having a pocket or receptacle welded in place to the sole plate within the club head. A weld-resistant metal is placed within the receptacle, prior to welding. No adjustment of the location or quantity of the weight is possible after installation.

Finally, Japanese Patent No. 2004-121,362 published on Apr. 22, 2004, illustrates further variations on a metal wood-type club head having a fixed, non-adjustable weight or mass installed therein.

None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed. Thus, a golf club head with an adjustable center of mass solving the aforementioned problems is desired.

SUMMARY OF THE INVENTION

The golf club head with adjustable center of mass includes a generally L-shaped arm having a club head attachment end and an opposite mass attachment end. An open socket or receptacle is provided in the sole of the club head, into which the club head attachment end of the arm seats. A cover plate is installed over the end of the arm and within the socket in order to preclude capture of dirt and debris within the socket during use of the club and to clamp the mass arm tightly within the receptacle. A series of detents is provided within the socket, with the attachment end of the arm having a mating configuration in order to lock the arm at the desired one of a series of specific angles or positions in the detents.

The arm may be adjusted to face forwardly, rearwardly, or to the left or right relative to the club face, or at some intermediate position between any of the above cardinal positions, to adjust the action of the club. Orienting the mass toward the hosel and shaft of the club places the mass of the club head between the center of the club and hosel, and results in a hook or draw (or correction of the opposite slice or fade). Positioning the mass in the opposite direction will, of course, have the opposite effect. Positioning the mass toward the front of the club head results in a lower loft or arcuate flight of the ball when struck, while positioning the mass toward the rear of the club head has the opposite effect. The arm also affects the vibrational characteristics of the club, depending upon the materials from which the arm and its weight are formed.

These and other features of the present invention will become readily apparent upon further review of the following specification and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of the golf club head with adjustable center of mass according to the present invention, showing the separation of the arm and weight from the club head.

FIG. 2A is a front elevation view of the golf club head of the present invention showing the initial position of the weight and arm during installation into the club head.

FIG. 2B is a front elevation view of the golf club head of the present invention showing an intermediate position of the weight and arm during installation into the club head.

FIG. 2C is a front elevation view of the golf club head of the present invention showing the nearly completed installation of the weight and arm into the club head.

FIG. 3 is a detailed, exploded bottom plan view of the arm and mass of the golf club head of the present invention.

FIG. 4 is a bottom plan view of the adjustable mass club head of the present invention, showing a series of cardinal positions for the adjustably positionable arm and mass therein.

FIG. 5 is a top plan view of the golf club head of the present invention, showing the twisting effects on the club head and shaft during a swing when the weight is oriented laterally.

FIG. 6 is a side elevation view of the golf club head of the present invention showing the rearward positioning of the adjustable weight and corresponding bending of the shaft during a swing.

Similar reference characters denote corresponding features consistently throughout the attached drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is a hollow golf club head having an adjustably positionable mass therein, providing the club head with an adjustable collective center of mass. The adjustable center of mass is used to adjust the loft, draw (hook) and fade (slice) tendencies of the club and golfer combination during play.

FIG. 1 of the drawings is an exploded perspective view of a hollow “metal wood” club head 10 of the present invention, i.e., a club head formed as a hollow, thin wall metal casting, but having the form of a conventional wood club head (e.g., driver, three wood, etc.) that would otherwise be formed of an essentially solid block or laminates of wood. Accordingly, the club head 10 includes a bottom or sole plate 12, a club face 14 at the front of the club head 10, a rear club head portion 16, a heel portion 18 having a club shaft hosel 20 extending therefrom, and a toe portion 22 opposite the heel portion 18. These various portions of the club head 10, along with the closed upper surface or wall of the club head 10, define a hollow interior 24 for the club head 10.

The hollow interior of the club head 10 is normally closed, but is accessible by an open weight installation receptacle passage 26 formed through the sole plate 12 of the club head. The receptacle passage 26 includes a recessed annular flange 28 surrounding the passage and extending inwardly toward the center of the passage 26. The flange 28 includes at least one detent 30 thereon, serving to lock the position of the adjustably positionable mass relative to the club head 10, as explained further below. The larger diameter portion 32 of the receptacle 26 is threaded to accept a matingly threaded receptacle cap 34 therein, with the cap 34 also securing an adjustably positionable mass immovably within the club head 10. The cap 34 is configured to have its exterior surface disposed essentially flush with the sole plate 12 of the club head 10 when the adjustable mass and cap 34 are properly secured in the club head.

A series of index markings, e.g., 36 a through 36 f (more or fewer may be provided), may be provided surrounding the receptacle 26 on the sole plate 12 surface of the club head 10. Corresponding legends, e.g., 38 a through 38 d (more or fewer may be provided), are also provided surrounding the receptacle 26 and index markings 36 a through 36 f, to indicate the proper orientation of the adjustably positionable mass within the club head 10 in order to achieve the desired effect or result.

An adjustably positionable rotary mass 40 is removably installed within the club head 10 through the weight installation receptacle 26. The rotary mass 40 has a unitary, monolithic, generally L-shaped configuration, with a club head attachment leg 42 and club head attachment end 44, and an opposite weighted leg 46 and weighted end 48. The weighted leg 46 and its end 48 are cantilevered from the club head attachment leg 42 and end 44, and describe a circular path within the hollow interior volume 24 of the club head 10 as the club head attachment end 44 is adjustably rotated within its club head receptacle 26.

The club head attachment end 44 of the L-shaped rotary mass 40 is configured to fit closely within the base of the mass or weight installation receptacle 26, adjacent the inset flange 28. The club head attachment end 44 of the mass arm 40 has a generally circular configuration, with a series of circumferentially disposed notches 50 that engage the detent or detents 30 of the flange 28. Preferably, several evenly spaced notches 50 are provided, allowing the mass 40 to be positioned in any of several orientations within the club head 10 radiating from the weight installation receptacle 26.

FIGS. 2A through 2C illustrate the installation of the L-shaped rotary mass 40 within the club head 10. In FIG. 2A, the weighted leg 46 of the mass 40 has been inserted through the receptacle opening or passage 26 and partially into the hollow interior volume 24 of the club head 10. As the L-shaped weight or mass 40 is inserted further into the interior 24 of the club head 10, it is turned as the elbow of the device, i.e., the juncture of the two legs 42 and 46, passes through the opening 26. The mass arm 40 is finally installed in the position shown in broken lines in FIG. 6, with the weighted leg 46 generally parallel to the sole plate 12 of the club head and the club head attachment leg 42 extending inwardly into the club head 10 and generally normal to the sole plate 12.

FIG. 3 provides an exploded detail plan view of the rotary weight or mass 40 of the device, including a plan view of the club head attachment end or flange 44. The club head attachment end 44 of the device, with its radial array of notches 50, which selectively engage the detents 30 at the base of the receptacle 26, are clearly shown in FIG. 3. While an array of twelve notches 50 is shown, providing twelve different angular positions for the weight arm 46 separated radially by thirty degrees each, it will be seen that more or fewer such notches may be provided for finer or more coarse positional adjustment of the weight 40, as desired.

It will be noted that a positional indicator 52 is disposed across the external face of the club head attachment end 44 of the rotary mass 40. The indicator 52 is preferably aligned with the weight leg 46 of the device 40, so a golfer may determine at a glance the orientation of the weight leg 46 within the hollow volume 24 of the club head 10. The indicator 52 will point toward one of the legends 38 a through 38 d disposed upon the sole plate 12 of the club head 10, and/or align with one of the index markings 36 a through 36 f, when the club head attachment end or flange 44 is securely seated in the receptacle 26 of the club head 10. This allows the golfer to readily determine the orientation of the weighted leg 46 within the club head 10, and to judge the corresponding characteristics of the club produced by a given orientation of the mass arm 40 within the club head 10.

While the weight or mass arm 40 itself is formed as a unitary, monolithic component, adjustment of the mass may be provided by adjustably or removably affixing an additional weight or mass 54 to the weighted leg end 48 of the device. The weighted leg 46 includes a concentric internally tapered threaded passage 56, with the supplemental weight 54 having a correspondingly tapered threaded shank 58 extending from its head 60. The threaded shank 58 of the supplemental weight 54 is secured within the threaded passage 56 of the weighted leg 46 of the rotary mass or arm 40 and adjusted as desired to provide a longer or shorter overall leg length, and thus a greater or smaller moment, for the weighted leg 46 and supplemental mass 54. It will be seen that further adjustment may be achieved by using different supplemental masses, or by adding or removing washers or spacers (not shown) between the head 60 of the supplemental weight 54 and the weight leg end 48 of the rotary mass 40, as desired.

The above described mass arm 40 and its supplemental weight or mass 54 may also provide benefits in the control of vibration of the club head and shaft during a golf stroke, as well as having an effect on the angle of the club face 14 when the ball is struck. It will be seen that the hollow club head 10 and its shaft (not shown), particularly in combination with the adjustably positionable cantilevered mass arm 40, will have certain vibration or resonance characteristics. These resonance or vibration characteristics may be controlled or affected by adjusting the material from which the rotatable mass arm 40 is formed, and/or coating the arm 40, or at least the weighted leg portion 46, with a vibration damping coating 62 (e.g., plastic of predetermined density and hardness, etc.) Plastic or other suitable coating material may be used where the mass 40 is formed of metal, or alternatively the entire mass 40 may be formed of a unitary, monolithic vibration damping material, as desired.

FIG. 4 provides a schematic bottom plan view of the present golf club head 10, showing a series of four different positions for the adjustable mass arm component 40 therein and corresponding shift in the center of gravity of the club head 10. The original center of gravity, CG₀, is shown aligned with the club head hosel 20. However, the installation and adjustment of the adjustably positionable mass 40 of the present invention will shift the collective center of gravity of the club head 10, and thus the entire head and shaft assembly of the club, depending upon the orientation of the weighted leg 46. If the weighted leg of the adjustable mass is oriented forwardly, i.e., toward the club face 14, as indicated by weighted leg position 46 ₁, the collective center of gravity of the club head and mass assembly is also shifted by a corresponding amount to a slightly forward location at CG₁. Alternatively, if the mass arm is turned 180° toward the back 16 of the club head to the position indicated by leg 46 ₂, the center of gravity is shifted by a corresponding amount to approximately the position shown as CG₂. Similar changes occur when the weighted leg is shifted toward the heel 18 or toe 22 of the club head 10, with the heel orientation of the weighted leg shown as 46 ₃ and its corresponding center of gravity at CG₃, and the toe orientation of the leg shown as 46 ₄ and corresponding center of gravity at CG₄. Greater or lesser displacements of the center of gravity may be provided, depending upon the mass of the weighted leg 46 and its supplemental weight (if any), and the mass of the club head 10 and its shaft, particularly near the hosel 20.

FIG. 5 of the drawings provides a top plan view of the club head 10, showing the effects of the club heel or club toe orientation of the mass arm on the fade and draw (slice and hook) characteristics of the club. In FIG. 5, two alternative positions are shown for the weighted leg, i.e., inwardly toward the heel 18 or hosel 20 of the club head 10, as weighted leg position 46 ₃, and outwardly toward the toe portion 22 of the club head 10, as weighted leg position 46 ₄. These two weighted leg positions 46 ₃ and 46 ₄ are equivalent to the positions 46 ₃ and 46 ₄ shown in FIG. 5 of the drawings.

When the mass arm is turned inwardly to the position shown as weighted leg 46 ₃ in FIG. 5, the collective mass of the club head and adjustable mass is shifted slightly inward, i.e., toward the heel 18 and hosel 20 of the club head 10. The greater mass to the inboard portion of the club head 10 results in a tendency for that portion of the club head to lag slightly behind the outer portion of the club head as the golfer accelerates the club head during the swing. This causes the club face to be turned slightly inward, i.e., toward the golfer, during the accelerating portion of the swing, as indicated by the displaced club face position 14 ₃ shown in broken lines in FIG. 5. (The angular displacement of the club face due to this effect is greatly exaggerated in FIG. 5, for clarity in the drawing Fig.) This adjustment can be quite valuable for a golfer who has a tendency to slice or fade the ball, i.e., to strike the ball to produce a flight path angling to the right of the ideal path (for a right-handed golfer).

When the mass arm is turned outwardly toward the toe 22 of the club head 10, as shown by the weighted leg position 46 ₄ in FIG. 5, a generally opposite result occurs. The shifting of the center of gravity of the club head and mass assembly toward the outer portion or toe of the club head 10, as indicated by the center of gravity position CG₄ in FIG. 5, causes the outer portion of the club head 10 to lag slightly as the club is accelerated in its swing. This results in the club face 14 being turned slightly outwardly away from the golfer, somewhat as shown by the displaced face position 14 ₄ in FIG. 5. It will be seen that this serves to correct a tendency for a golfer to hook or draw the ball, i.e., strike the ball to produce a flight path to the left of the desired path (for a right-handed golfer).

The effects are somewhat different when the weighted leg 46 is adjusted to a forwardly or rearwardly disposed position within the club head. The effect of the rearward adjustment of the weighted arm is shown in FIG. 6 of the drawings, with forward adjustment producing an opposite effect. In FIG. 6, the weighted leg has been adjusted rearwardly within the club head 10, to a position 46 ₂ as shown in FIGS. 4 and 6. This results in the adjustment of the center of gravity rearwardly in the club head to the new center of gravity position CG₂, rearward of the axis of the club shaft S.

When the club is swung, centrifugal force shifts the center of gravity CG₂ radially outwardly by a small displacement D₁. As the new center of gravity CG₂ is not aligned with the axis of the club shaft S, this has the effect of lowering the rear of the club head 10. As the forward portion of the club head 10 is immovably affixed to the shaft S, the result is a slight bending of the club shaft S, causing the club shaft S and club head 10 to shift forwardly by a displacement D₂ and take the position shown in broken lines in FIG. 6. (The bending of the club shaft S and altered position of the club head 10 in broken lines, are greatly exaggerated in FIG. 6 for clarity in the drawing.)

This bending of the club shaft S shifts the angle of the club head 10, and thus the club face 14, relative to the upper portion of the club shaft S. The forward displacement of the club head 10 relative to the upper portion of the club shaft S results in an angular displacement of the club face 14, altering the dynamic loft angle L of the club face to the slightly shallower angle shown in broken lines. (Again, the various displacement effects are greatly exaggerated for clarity.) Adjustment of the weighted leg to a forward position within the club head 10 will be seen to produce the opposite effect, i.e., to reduce the effective dynamic loft angle of the club. This adjustability can be of great assistance to a golfer who requires a club having a loft angle between two standard clubs, and/or who wishes to eliminate certain clubs from his golf bag by providing a single universal metal wood club that is adjustable for different characteristics.

In conclusion, the present golf club head with its adjustable center of mass is a most useful addition to the collection of clubs owned and used by the serious golfer. A golfer who has a consistent tendency to draw or fade the ball, particularly from the tee, can adjust such tendencies out of his or her swing by means of the adjustability of the present club. Moreover, the golfer may adjust the effective or dynamic loft of the present club to make fine adjustments thereto, perhaps finding that carrying an intermediate club (e.g., a two wood) equipped with the present adjustable center of mass may be used to replace the conventional driver and three wood as well. The golfer need only remove the protective cap from the weight receptacle, adjust the radial position of the adjustable mass according to the index markings and legend on the sole plate of the club head, and replace the cap to secure the mass in the desired position. This adjustability and versatility of the present club will be most appreciated by golfers of virtually all levels of skill and expertise.

It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims. 

1. A golf club head with an adjustable center of mass, comprising: a golf club head having at least a sole plate, the sole plate having an open weight installation receptacle formed therethrough, a club face defining the front of said golf club head, a rear portion opposite the club face, a heel portion having a hosel extending therefrom, and a toe portion opposite the heel portion, the head having a hollow interior; and a unitary, monolithic, generally L-shaped arm having a club head attachment leg terminating in a club head attachment end and having a weighted leg generally normal to the club head attachment leg terminating in a weighted end opposite the club head attachment end, the L-shaped arm being removably and adjustably secured within the weight installation receptacle and hollow interior of said club head.
 2. The golf club head according to claim 1, further including: an index disposed externally upon the sole plate of said golf club head and surrounding the weight installation receptacle; and an indicator disposed upon the club head attachment end of said L-shaped arm, corresponding with said index when said L-shaped arm is installed within the weight installation receptacle.
 3. The golf club head according to claim 1, further including at least one detent disposed within the weight installation receptacle, the club head attachment end of said L-shaped arm having a configuration selectively engaging the at least one detent of the weight installation receptacle and orienting the weighted end of said L-shaped arm within said club head.
 4. The golf club head according to claim 1, further including a removable and adjustably positionable mass disposed upon the weighted end of said L-shaped arm.
 5. The golf club head according to claim 1, further including a receptacle cap removably disposed over the weight installation receptacle for securing said L-shaped arm therein when installed.
 6. The golf club head according to claim 1, wherein at least said L-shaped arm is formed of a material selected from the group consisting of a metal core having a vibration damping coating, and a vibration damping material.
 7. A golf club head with an adjustable center of mass, comprising: a golf club head having at least a sole plate, the sole plate having an open weight installation receptacle formed therethrough, a club face defining the front of said golf club head, a rear portion opposite the club face, a heel portion having a hosel extending therefrom, and a toe portion opposite the heel portion, the head having a hollow interior; a rotary mass adjustably disposed within the hollow interior of said golf club head, said rotary mass having at least a club head attachment end secured to the weight installation receptacle; an index disposed externally upon the sole plate of said golf club head and surrounding the weight installation receptacle; and an indicator disposed upon the club head attachment end of said rotary mass and corresponding with said index when said rotary mass is installed within the weight installation receptacle.
 8. The golf club head according to claim 7, wherein said rotary mass comprises a unitary, monolithic, generally L-shaped arm having a club head attachment leg terminating in a club head attachment end, and having a weighted leg normal to the club head attachment leg terminating in a weighted end opposite the club head attachment end.
 9. The golf club head according to claim 7, further including at least one detent disposed within the weight installation receptacle, the club head attachment end of said rotary mass having a configuration selectively engaging the at least one detent of the weight installation receptacle and orienting the weighted end of said rotary mass within said club head.
 10. The golf club head according to claim 7, further including a removable and adjustably positionable mass disposed upon the weighted end of said rotary mass.
 11. The golf club head according to claim 7, further including a receptacle cap removably disposed over the weight installation receptacle for securing said rotary mass therein when installed.
 12. The golf club head according to claim 7, wherein at least said rotary mass is formed of a material selected from the group consisting of a metal core having a vibration damping coating, and a vibration damping material.
 13. A golf club head with an adjustable center of mass, comprising: a golf club head having at least a sole plate, the sole plate having an open weight installation receptacle formed therethrough, a club face defining the front of said golf club head, a rear portion opposite the club face, a heel portion having a hosel extending therefrom, and a toe portion opposite the heel portion, the head having a hollow interior; a rotary mass adjustably disposed within the hollow interior of said golf club head, said rotary mass having at least a club head attachment end secured to the weight installation receptacle; and at least one detent disposed within the weight installation receptacle, the club head attachment end of said rotary mass having a configuration selectively engaging the at least one detent of the weight installation receptacle and orienting the weighted end of said rotary mass within said club head in a user-selectable orientation.
 14. The golf club head according to claim 13, wherein said rotary mass comprises a unitary, monolithic, generally L-shaped arm having a club head attachment leg terminating in a club head attachment end and having a weighted leg normal to the club head attachment leg terminating in a weighted end opposite the club head attachment end.
 15. The golf club head according to claim 13, further including: an index disposed externally upon the sole plate of said golf club head and surrounding the weight installation receptacle; and an indicator disposed upon the club head attachment end corresponding with said index when said rotary mass is installed within the weight installation receptacle.
 16. The golf club head according to claim 13, further including a removable and adjustably positionable mass disposed upon the weighted end of said rotary mass.
 17. The golf club head according to claim 13, further including a receptacle cap removably disposed over the weight installation receptacle for securing said rotary mass therein when installed.
 18. The golf club head with an adjustable center of mass according to claim 13, wherein at least said rotary mass is formed of a material selected from the group consisting of a metal core having a vibration damping coating, and a vibration damping material. 